Description:

Medulloblastoma (MB), an embryonal cerebellar tumor, comprises four major molecularly, histopathologically and clinically distinct subgroups: Sonic Hedgehog (SHH), Wingless (WNT), Group3 (G3) and Group4 (G4). Compared to other cancers, MBs have a relative paucity of mutations affecting known oncogenes and tumor suppressors (β-CATENIN, PATCHED, SUFU, GLI2, MYC and MYCN) that account for only 20-30% of overall cases. Next generation genome sequencing revealed additional somatically altered genes, many of which play roles in epigenetic regulation and chromatin modification. Remarkably, some tumors have no reported mutations, suggesting that some genes required for oncogenesis might be regulated by epigenetic mechanisms.